In the field of an organic light-emitting device such as an organic electroluminescent device (organic EL device) or the like, developments are being carried out for the purpose of attaining high emission efficiency for each of blue emission, green emission and red emission. Further, also for an organic light-emitting device constructed to emit white color by combining these emission colors (organic white light-emitting diode), investigations relating to combination and layer configuration of light-emitting materials that can realize high emission efficiency are being promoted.
For example, NPL 1 describes insertion of spacer layers between plural phosphorescent material-containing layers in a system using a phosphorescent material. The literature discloses, as an example thereof, an organic light-emitting device having a layer containing a blue phosphorescent material, a mixed layer containing a green phosphorescent material and a red phosphorescent material mixed therein, and a spacer layer existing between these layers. When a blue phosphorescent material, a green phosphorescent material and a red phosphorescent material are mixed to exist in one and the same layer, energy transfer from the high-energy blue phosphorescent material to the green phosphorescent material and further from the green phosphorescent material to the red phosphorescent material is easy, and therefore, for realizing well-balanced emission from every phosphorescent material, precise density control is needed. Contrary to this, when the blue phosphorescent material, the green phosphorescent material and the red phosphorescent material are separated from each other via a spacer layer therebetween, energy transfer from the blue phosphorescent material to the other phosphorescent materials can be prevented by the spacer layer and therefore it is said that well-balanced emission from each phosphorescent material would be realized.